This application describe a five year prospective longitudinal study of visual function in glaucoma, which builds upon prior work in this area during the previous grant period. This study will use a variety of psychophysical tests of visual function to determine the nature and extent of functional loss associated with this disease. Specific Aims 1) To use a multivariate approach for analysis of the functional changes in vision associated with glaucoma and to delineate further the relationship of these changes to the underlying physiological mechanisms associated with magnocellular and parvocellular pathways. 2) To develop clinically relevant, reliable and reproducible multivariate methods for early diagnosis of primary open angle glaucoma and for monitoring its progression. 3) To determine the time course of and relationship between recognizable optic nerve damage and measurable loss of visual functions on the same group of normal, glaucoma suspect, and glaucomatous individuals in a prospective five year longitudinal study will help to define the nature of these functional change. 4) To use the multivariate approach to increase the precision with which progressive glaucoma can be diagnosed and to use this paradigm to follow glaucoma suspect patients in a prospective 5 year longitudinal study to determine their risk for development of the disease. 5) To determine the age-related change for a variety of isolated visual functions in normal healthy eyes, who will also serve as normal controls for the psychophysical tests. Subjects. The study will include 100 age-matched normal controls. Methods. The psychophysical tests are designed to isolate various visual functions. Many of these subjects already have five years of results on short-wavelength automated perimetry and standard perimetry, so that a subset of this proposal's total population will have nine or ten years of data with these. In addition, High-pass Resolution Perimetry, Spatial Contrast Sensitivity, Motion Perception, and Temporal Modulation Flicker will be evaluated. The results of these test along with clinical determinations of development and progression of glaucoma will allow us to address each of the specific aims outlined above, and to improve understanding of the changes in visual function and associated mechanisms underlying those changes.